This new pair of callbacks allows plugins to describe which extents in the virtual disk are allocated, holes or zeroes. --- docs/nbdkit-filter.pod | 83 ++++++++++++++++ docs/nbdkit-plugin.pod | 97 +++++++++++++++++++ include/nbdkit-common.h | 10 +- include/nbdkit-filter.h | 22 ++++- include/nbdkit-plugin.h | 6 +- server/internal.h | 4 + server/extents.c | 210 ++++++++++++++++++++++++++++++++++++++++ server/filters.c | 59 +++++++++++ server/plugins.c | 54 ++++++++++- server/Makefile.am | 1 + server/nbdkit.syms | 5 + 11 files changed, 547 insertions(+), 4 deletions(-) diff --git a/docs/nbdkit-filter.pod b/docs/nbdkit-filter.pod index dc9a262..9e51c68 100644 --- a/docs/nbdkit-filter.pod +++ b/docs/nbdkit-filter.pod @@ -350,6 +350,8 @@ calls. =head2 C<.can_zero> +=head2 C<.can_extents> + =head2 C<.can_fua> =head2 C<.can_multi_conn> @@ -365,6 +367,8 @@ calls. void *handle); int (*can_zero) (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle); + int (*can_extents) (struct nbdkit_next_ops *next_ops, void *nxdata, + void *handle); int (*can_fua) (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle); int (*can_multi_conn) (struct nbdkit_next_ops *next_ops, void *nxdata, @@ -513,6 +517,85 @@ value to return to the client. The filter should never fail with C<EOPNOTSUPP> (while plugins have automatic fallback to C<.pwrite>, filters do not). +=head2 C<.extents> + + int (*extents) (struct nbdkit_next_ops *next_ops, void *nxdata, + void *handle, uint32_t count, uint64_t offset, uint32_t flags, + struct nbdkit_extents *extents, + int *err); + +This intercepts the plugin C<.extents> method and can be used to +modify extent requests. + +This function will not be called if C<.can_extents> returned false; in +turn, the filter should not call C<next_ops-E<gt>extents> if +C<next_ops-E<gt>can_extents> did not return true. + +It is possible for filters to transform the extents list received back +from the layer below. Without error checking it would look like this: + + myfilter_extents (..., uint32_t count, uint64_t offset, ...) + { + size_t i; + struct nbdkit_extents *extents2; + struct nbdkit_extent e; + int64_t size; + + size = next_ops->get_size (nxdata); + extents2 = nbdkit_extents_new (offset + shift, size - shift); + next_ops->extents (nxdata, count, offset + shift, flags, extents2, err); + for (i = 0; i < nbdkit_extents_count (extents2); ++i) { + e = nbdkit_get_extent (extents2, i); + e.offset -= shift; + nbdkit_add_extent (extents, e.offset, e.length, e.type); + } + nbdkit_extents_free (extents2); + } + +If there is an error, C<.extents> should call C<nbdkit_error> with an +error message B<and> return -1 with C<err> set to the positive errno +value to return to the client. + +=head3 Allocating and freeing nbdkit_extents list + +Two functions are provided to filters only for allocating and freeing +the map: + + struct nbdkit_extents *nbdkit_extents_new (uint64_t start, uint64_t end); + +Allocates and returns a new, empty extents list. The C<start> +parameter is the start of the range described in the list, and the +C<end> parameter is the offset of the byte beyond the end. Normally +you would pass in C<offset> as the start and the size of the plugin as +the end, but for filters which adjust offsets, they should pass in the +adjusted offset. + +On error this function can return C<NULL>. In this case it calls +C<nbdkit_error> and/or C<nbdkit_set_error> as required. + + void nbdkit_extents_free (struct nbdkit_extents *); + +Frees an existing extents list. + +=head3 Iterating over nbdkit_extents list + +Two functions are provided to filters only to iterate over the extents +in order: + + size_t nbdkit_extents_count (const struct nbdkit_extents *); + +Returns the number of extents in the list. + + struct nbdkit_extent { + uint64_t offset; + uint64_t length; + uint32_t type; + }; + struct nbdkit_extent nbdkit_get_extent (const struct nbdkit_extents *, + size_t i); + +Returns a copy of the C<i>'th extent. + =head1 ERROR HANDLING If there is an error in the filter itself, the filter should call diff --git a/docs/nbdkit-plugin.pod b/docs/nbdkit-plugin.pod index 47545f3..272ec67 100644 --- a/docs/nbdkit-plugin.pod +++ b/docs/nbdkit-plugin.pod @@ -555,6 +555,20 @@ This callback is not required. If omitted, then nbdkit always tries C<.zero> first if it is present, and gracefully falls back to C<.pwrite> if C<.zero> was absent or failed with C<EOPNOTSUPP>. +=head2 C<.can_extents> + + int can_extents (void *handle); + +This is called during the option negotiation phase to find out if the +plugin supports detecting allocated (non-sparse) regions of the disk +with the C<.extents> callback. + +If there is an error, C<.can_extents> should call C<nbdkit_error> with +an error message and return C<-1>. + +This callback is not required. If omitted, then we return true iff a +C<.extents> callback has been defined. + =head2 C<.can_fua> int can_fua (void *handle); @@ -717,6 +731,89 @@ If there is an error, C<.zero> should call C<nbdkit_error> with an error message, and C<nbdkit_set_error> to record an appropriate error (unless C<errno> is sufficient), then return C<-1>. +=head2 C<.extents> + + int extents (void *handle, uint32_t count, uint64_t offset, + uint32_t flags, struct nbdkit_extents *extents); + +During the data serving phase, this callback is used to detect +allocated, sparse and zeroed regions of the disk. + +This function will not be called if C<.can_extents> returned false. +nbdkit's default behaviour in this case is to treat the whole virtual +disk as if it was allocated. + +The callback should detect and return the list of extents overlapping +the range C<[offset...offset+count-1]>. The C<extents> parameter +points to an opaque object which the callback should fill in by +calling C<nbdkit_add_extent>. See L</Extents list> below. + +If there is an error, C<.extents> should call C<nbdkit_error> with an +error message, and C<nbdkit_set_error> to record an appropriate error +(unless C<errno> is sufficient), then return C<-1>. + +=head3 Extents list + +The plugin C<extents> callback is passed an opaque pointer C<struct +nbdkit_extents *extents>. This structure represents a list of +L<filesystem extents|https://en.wikipedia.org/wiki/Extent_(file_systems)> +describing which areas of the disk are allocated, which are sparse +(“holes”), and, if supported, which are zeroes. + +The C<extents> callback should scan the disk starting at C<offset> and +call C<nbdkit_add_extent> for each extent found. + +Extents overlapping the range C<[offset...offset+count-1]> should be +returned if possible. However nbdkit ignores extents E<lt> offset so +the plugin may, if it is easier to implement, return all extent +information for the whole disk. The plugin may return extents beyond +the end of the range. It may also return extent information for less +than the whole range, but it must return at least one extent +overlapping C<offset>. + +The extents B<must> be added in ascending order, and B<must> be +contiguous. + +The C<flags> parameter of the C<.extents> callback may contain the +flag C<NBDKIT_FLAG_REQ_ONE>. This means that the client is only +requesting information about the extent overlapping C<offset>. The +plugin may ignore this flag, or as an optimization it may return just +a single extent for C<offset>. + + int nbdkit_add_extent (struct nbdkit_extents *extents, + uint64_t offset, uint64_t length, uint32_t type); + +Add an extent covering C<[offset...offset+length-1]> of one of +the following four types: + +=over 4 + +=item C<type = 0> + +A normal, allocated data extent. + +=item C<type = NBDKIT_EXTENT_HOLE|NBDKIT_EXTENT_ZERO> + +An unallocated extent, a.k.a. a “hole”, which reads back as zeroes. +This is the normal type of hole applicable to most disks. + +=item C<type = NBDKIT_EXTENT_ZERO> + +An allocated extent which is known to contain only zeroes. + +=item C<type = NBDKIT_EXTENT_HOLE> + +An unallocated extent (hole) which does not read back as zeroes. Note +this should only be used in specialized circumstances such as when +writing a plugin for (or to emulate) certain SCSI drives which do not +guarantee that trimmed blocks read back as zeroes. + +=back + +C<nbdkit_extent_add> returns C<0> on success or C<-1> on failure. On +failure C<nbdkit_error> and/or C<nbdkit_set_error> has already been +called. + =head1 THREADS Each nbdkit plugin must declare its thread safety model by defining diff --git a/include/nbdkit-common.h b/include/nbdkit-common.h index cb9954e..7c69b14 100644 --- a/include/nbdkit-common.h +++ b/include/nbdkit-common.h @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2013-2018 Red Hat Inc. + * Copyright (C) 2013-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -60,11 +60,15 @@ extern "C" { #define NBDKIT_FLAG_MAY_TRIM (1<<0) /* Maps to !NBD_CMD_FLAG_NO_HOLE */ #define NBDKIT_FLAG_FUA (1<<1) /* Maps to NBD_CMD_FLAG_FUA */ +#define NBDKIT_FLAG_REQ_ONE (1<<2) /* Maps to NBD_CMD_FLAG_REQ_ONE */ #define NBDKIT_FUA_NONE 0 #define NBDKIT_FUA_EMULATE 1 #define NBDKIT_FUA_NATIVE 2 +#define NBDKIT_EXTENT_HOLE (1<<0) /* Same as NBD_STATE_HOLE */ +#define NBDKIT_EXTENT_ZERO (1<<1) /* Same as NBD_STATE_ZERO */ + extern void nbdkit_error (const char *msg, ...) ATTRIBUTE_FORMAT_PRINTF (1, 2); extern void nbdkit_verror (const char *msg, va_list args); extern void nbdkit_debug (const char *msg, ...) ATTRIBUTE_FORMAT_PRINTF (1, 2); @@ -76,6 +80,10 @@ extern int nbdkit_parse_bool (const char *str); extern int nbdkit_read_password (const char *value, char **password); extern char *nbdkit_realpath (const char *path); +struct nbdkit_extents; +extern int nbdkit_add_extent (struct nbdkit_extents *, + uint64_t offset, uint64_t length, uint32_t type); + /* A static non-NULL pointer which can be used when you don't need a * per-connection handle. */ diff --git a/include/nbdkit-filter.h b/include/nbdkit-filter.h index 71c06c8..026145b 100644 --- a/include/nbdkit-filter.h +++ b/include/nbdkit-filter.h @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2013-2018 Red Hat Inc. + * Copyright (C) 2013-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -44,6 +44,18 @@ extern "C" { #define NBDKIT_FILTER_API_VERSION 2 +struct nbdkit_extent { + uint64_t offset; + uint64_t length; + uint32_t type; +}; + +extern struct nbdkit_extents *nbdkit_extents_new (uint64_t start, uint64_t end); +extern void nbdkit_extents_free (struct nbdkit_extents *); +extern size_t nbdkit_extents_count (const struct nbdkit_extents *); +extern struct nbdkit_extent nbdkit_get_extent (const struct nbdkit_extents *, + size_t); + typedef int nbdkit_next_config (void *nxdata, const char *key, const char *value); typedef int nbdkit_next_config_complete (void *nxdata); @@ -58,6 +70,7 @@ struct nbdkit_next_ops { int (*is_rotational) (void *nxdata); int (*can_trim) (void *nxdata); int (*can_zero) (void *nxdata); + int (*can_extents) (void *nxdata); int (*can_fua) (void *nxdata); int (*can_multi_conn) (void *nxdata); @@ -71,6 +84,8 @@ struct nbdkit_next_ops { int *err); int (*zero) (void *nxdata, uint32_t count, uint64_t offset, uint32_t flags, int *err); + int (*extents) (void *nxdata, uint32_t count, uint64_t offset, uint32_t flags, + struct nbdkit_extents *extents, int *err); }; struct nbdkit_filter { @@ -120,6 +135,8 @@ struct nbdkit_filter { void *handle); int (*can_zero) (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle); + int (*can_extents) (struct nbdkit_next_ops *next_ops, void *nxdata, + void *handle); int (*can_fua) (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle); int (*can_multi_conn) (struct nbdkit_next_ops *next_ops, void *nxdata, @@ -140,6 +157,9 @@ struct nbdkit_filter { int (*zero) (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle, uint32_t count, uint64_t offset, uint32_t flags, int *err); + int (*extents) (struct nbdkit_next_ops *next_ops, void *nxdata, + void *handle, uint32_t count, uint64_t offset, uint32_t flags, + struct nbdkit_extents *extents, int *err); }; #define NBDKIT_REGISTER_FILTER(filter) \ diff --git a/include/nbdkit-plugin.h b/include/nbdkit-plugin.h index d43b2f5..20d193c 100644 --- a/include/nbdkit-plugin.h +++ b/include/nbdkit-plugin.h @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2013-2018 Red Hat Inc. + * Copyright (C) 2013-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -125,6 +125,10 @@ struct nbdkit_plugin { const char *magic_config_key; int (*can_multi_conn) (void *handle); + + int (*can_extents) (void *handle); + int (*extents) (void *handle, uint32_t count, uint64_t offset, uint32_t flags, + struct nbdkit_extents *extents); }; extern void nbdkit_set_error (int err); diff --git a/server/internal.h b/server/internal.h index d40a82d..71d2815 100644 --- a/server/internal.h +++ b/server/internal.h @@ -274,6 +274,7 @@ struct backend { int (*is_rotational) (struct backend *, struct connection *conn); int (*can_trim) (struct backend *, struct connection *conn); int (*can_zero) (struct backend *, struct connection *conn); + int (*can_extents) (struct backend *, struct connection *conn); int (*can_fua) (struct backend *, struct connection *conn); int (*can_multi_conn) (struct backend *, struct connection *conn); @@ -287,6 +288,9 @@ struct backend { uint64_t offset, uint32_t flags, int *err); int (*zero) (struct backend *, struct connection *conn, uint32_t count, uint64_t offset, uint32_t flags, int *err); + int (*extents) (struct backend *, struct connection *conn, uint32_t count, + uint64_t offset, uint32_t flags, + struct nbdkit_extents *extents, int *err); }; /* plugins.c */ diff --git a/server/extents.c b/server/extents.c new file mode 100644 index 0000000..549d39f --- /dev/null +++ b/server/extents.c @@ -0,0 +1,210 @@ +/* nbdkit + * Copyright (C) 2019 Red Hat Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * * Neither the name of Red Hat nor the names of its contributors may be + * used to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A + * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT + * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <config.h> + +#include <stdio.h> +#include <stdlib.h> +#include <stdint.h> +#include <stdbool.h> +#include <string.h> +#include <inttypes.h> +#include <errno.h> +#include <assert.h> + +#include "minmax.h" + +#include "internal.h" + +struct nbdkit_extents { + struct nbdkit_extent *extents; + size_t nr_extents, allocated; + uint64_t start, end; /* end is one byte beyond the end of the range */ +}; + +struct nbdkit_extents * +nbdkit_extents_new (uint64_t start, uint64_t end) +{ + struct nbdkit_extents *r; + + if (start >= INT64_MAX || end >= INT64_MAX) { + nbdkit_error ("nbdkit_extents_new: " + "start (%" PRIu64 ") or end (%" PRIu64 ") >= INT64_MAX", + start, end); + errno = ERANGE; + return NULL; + } + + /* 0-length ranges are possible, so start == end is not an error. */ + if (start > end) { + nbdkit_error ("nbdkit_extents_new: " + "start (%" PRIu64 ") >= end (%" PRIu64 ")", + start, end); + errno = ERANGE; + return NULL; + } + + r = malloc (sizeof *r); + if (r == NULL) { + nbdkit_error ("nbdkit_extents_new: malloc: %m"); + return NULL; + } + r->extents = NULL; + r->nr_extents = r->allocated = 0; + r->start = start; + r->end = end; + return r; +} + +void +nbdkit_extents_free (struct nbdkit_extents *exts) +{ + if (exts) { + free (exts->extents); + free (exts); + } +} + +size_t +nbdkit_extents_count (const struct nbdkit_extents *exts) +{ + return exts->nr_extents; +} + +const struct nbdkit_extent +nbdkit_get_extent (const struct nbdkit_extents *exts, size_t i) +{ + assert (i < exts->nr_extents); + return exts->extents[i]; +} + +/* Insert *e in the list at the end. */ +static int +append_extent (struct nbdkit_extents *exts, const struct nbdkit_extent *e) +{ + if (exts->nr_extents >= exts->allocated) { + size_t new_allocated; + struct nbdkit_extent *new_extents; + + new_allocated = exts->allocated; + if (new_allocated == 0) + new_allocated = 1; + new_allocated *= 2; + new_extents = + realloc (exts->extents, new_allocated * sizeof (struct nbdkit_extent)); + if (new_extents == NULL) { + nbdkit_error ("nbdkit_add_extent: realloc: %m"); + return -1; + } + exts->allocated = new_allocated; + exts->extents = new_extents; + } + + exts->extents[exts->nr_extents] = *e; + exts->nr_extents++; + return 0; +} + +int +nbdkit_add_extent (struct nbdkit_extents *exts, + uint64_t offset, uint64_t length, uint32_t type) +{ + uint64_t overlap; + + if (length == 0) + return 0; + + /* Ignore extents beyond the end of the range. Unfortunately we + * lost the information about whether this is contiguous with a + * previously added extent so we can't check for API usage errors. + */ + if (offset >= exts->end) + return 0; + + /* Shorten extents that overlap the end of the range. */ + if (offset + length >= exts->end) { + overlap = offset + length - exts->end; + length -= overlap; + } + + /* If there are existing extents, the new extent must be contiguous. */ + if (exts->nr_extents > 0) { + const struct nbdkit_extent *ep; + + ep = &exts->extents[exts->nr_extents-1]; + if (offset != ep->offset + ep->length) { + nbdkit_error ("nbdkit_add_extent: " + "extents must be added in ascending order and " + "must be contiguous"); + return -1; + } + } + else { + /* If there are no existing extents, and the new extent is + * entirely before start, ignore it. + */ + if (offset + length <= exts->start) + return 0; + + /* If there are no existing extents, and the new extent is after + * start, then this is a bug in the plugin. + */ + if (offset > exts->start) { + nbdkit_error ("nbdkit_add_extent: " + "first extent must not be > start (%" PRIu64 ")", + exts->start); + return -1; + } + + /* If there are no existing extents, and the new extent overlaps + * start, truncate it so it starts at start. + */ + overlap = exts->start - offset; + length -= overlap; + offset += overlap; + } + + /* If we get here we are going to either add or extend. */ + if (exts->nr_extents > 0 && + exts->extents[exts->nr_extents-1].type == type) { + /* Coalesce with the last extent. */ + exts->extents[exts->nr_extents-1].length += length; + return 0; + } + else { + /* Add a new extent. */ + const struct nbdkit_extent e = + { .offset = offset, .length = length, .type = type }; + return append_extent (exts, &e); + } +} diff --git a/server/filters.c b/server/filters.c index 5b7abc4..5095188 100644 --- a/server/filters.c +++ b/server/filters.c @@ -309,6 +309,13 @@ next_can_zero (void *nxdata) return b_conn->b->can_zero (b_conn->b, b_conn->conn); } +static int +next_can_extents (void *nxdata) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->can_extents (b_conn->b, b_conn->conn); +} + static int next_can_fua (void *nxdata) { @@ -364,6 +371,15 @@ next_zero (void *nxdata, uint32_t count, uint64_t offset, uint32_t flags, return b_conn->b->zero (b_conn->b, b_conn->conn, count, offset, flags, err); } +static int +next_extents (void *nxdata, uint32_t count, uint64_t offset, uint32_t flags, + struct nbdkit_extents *extents, int *err) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->extents (b_conn->b, b_conn->conn, count, offset, flags, + extents, err); +} + static struct nbdkit_next_ops next_ops = { .get_size = next_get_size, .can_write = next_can_write, @@ -371,6 +387,7 @@ static struct nbdkit_next_ops next_ops = { .is_rotational = next_is_rotational, .can_trim = next_can_trim, .can_zero = next_can_zero, + .can_extents = next_can_extents, .can_fua = next_can_fua, .can_multi_conn = next_can_multi_conn, .pread = next_pread, @@ -378,6 +395,7 @@ static struct nbdkit_next_ops next_ops = { .flush = next_flush, .trim = next_trim, .zero = next_zero, + .extents = next_extents, }; static int @@ -511,6 +529,21 @@ filter_can_zero (struct backend *b, struct connection *conn) return f->backend.next->can_zero (f->backend.next, conn); } +static int +filter_can_extents (struct backend *b, struct connection *conn) +{ + struct backend_filter *f = container_of (b, struct backend_filter, backend); + void *handle = connection_get_handle (conn, f->backend.i); + struct b_conn nxdata = { .b = f->backend.next, .conn = conn }; + + debug ("%s: can_extents", f->name); + + if (f->filter.can_extents) + return f->filter.can_extents (&next_ops, &nxdata, handle); + else + return f->backend.next->can_extents (f->backend.next, conn); +} + static int filter_can_fua (struct backend *b, struct connection *conn) { @@ -646,6 +679,30 @@ filter_zero (struct backend *b, struct connection *conn, count, offset, flags, err); } +static int +filter_extents (struct backend *b, struct connection *conn, + uint32_t count, uint64_t offset, uint32_t flags, + struct nbdkit_extents *extents, int *err) +{ + struct backend_filter *f = container_of (b, struct backend_filter, backend); + void *handle = connection_get_handle (conn, f->backend.i); + struct b_conn nxdata = { .b = f->backend.next, .conn = conn }; + + assert (!(flags & ~NBDKIT_FLAG_REQ_ONE)); + + debug ("%s: extents count=%" PRIu32 " offset=%" PRIu64 " flags=0x%" PRIx32, + f->name, count, offset, flags); + + if (f->filter.extents) + return f->filter.extents (&next_ops, &nxdata, handle, + count, offset, flags, + extents, err); + else + return f->backend.next->extents (f->backend.next, conn, + count, offset, flags, + extents, err); +} + static struct backend filter_functions = { .free = filter_free, .thread_model = filter_thread_model, @@ -667,6 +724,7 @@ static struct backend filter_functions = { .is_rotational = filter_is_rotational, .can_trim = filter_can_trim, .can_zero = filter_can_zero, + .can_extents = filter_can_extents, .can_fua = filter_can_fua, .can_multi_conn = filter_can_multi_conn, .pread = filter_pread, @@ -674,6 +732,7 @@ static struct backend filter_functions = { .flush = filter_flush, .trim = filter_trim, .zero = filter_zero, + .extents = filter_extents, }; /* Register and load a filter. */ diff --git a/server/plugins.c b/server/plugins.c index 28b96ad..0b0fe77 100644 --- a/server/plugins.c +++ b/server/plugins.c @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2013-2018 Red Hat Inc. + * Copyright (C) 2013-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -199,6 +199,8 @@ plugin_dump_fields (struct backend *b) HAS (trim); HAS (zero); HAS (can_multi_conn); + HAS (can_extents); + HAS (extents); #undef HAS /* Custom fields. */ @@ -392,6 +394,21 @@ plugin_can_zero (struct backend *b, struct connection *conn) return plugin_can_write (b, conn); } +static int +plugin_can_extents (struct backend *b, struct connection *conn) +{ + struct backend_plugin *p = container_of (b, struct backend_plugin, backend); + + assert (connection_get_handle (conn, 0)); + + debug ("can_extents"); + + if (p->plugin.can_extents) + return p->plugin.can_extents (connection_get_handle (conn, 0)); + else + return p->plugin.extents != NULL; +} + static int plugin_can_fua (struct backend *b, struct connection *conn) { @@ -651,6 +668,39 @@ plugin_zero (struct backend *b, struct connection *conn, return r; } +static int +plugin_extents (struct backend *b, struct connection *conn, + uint32_t count, uint64_t offset, uint32_t flags, + struct nbdkit_extents *extents, int *err) +{ + struct backend_plugin *p = container_of (b, struct backend_plugin, backend); + bool req_one = flags & NBDKIT_FLAG_REQ_ONE; + int r; + + assert (connection_get_handle (conn, 0)); + assert (!(flags & ~NBDKIT_FLAG_REQ_ONE)); + + /* This should be true because plugin_can_extents checks it. */ + assert (p->plugin.extents); + + debug ("extents count=%" PRIu32 " offset=%" PRIu64 " req_one=%d", + count, offset, req_one); + + if (!count) + return 0; + + r = p->plugin.extents (connection_get_handle (conn, 0), count, offset, + flags, extents); + if (r >= 0 && nbdkit_extents_count (extents) < 1) { + nbdkit_error ("extents: plugin must return at least one extent"); + nbdkit_set_error (EINVAL); + r = -1; + } + if (r == -1) + *err = get_error (p); + return r; +} + static struct backend plugin_functions = { .free = plugin_free, .thread_model = plugin_thread_model, @@ -672,6 +722,7 @@ static struct backend plugin_functions = { .is_rotational = plugin_is_rotational, .can_trim = plugin_can_trim, .can_zero = plugin_can_zero, + .can_extents = plugin_can_extents, .can_fua = plugin_can_fua, .can_multi_conn = plugin_can_multi_conn, .pread = plugin_pread, @@ -679,6 +730,7 @@ static struct backend plugin_functions = { .flush = plugin_flush, .trim = plugin_trim, .zero = plugin_zero, + .extents = plugin_extents, }; /* Register and load a plugin. */ diff --git a/server/Makefile.am b/server/Makefile.am index be70700..5ee662e 100644 --- a/server/Makefile.am +++ b/server/Makefile.am @@ -43,6 +43,7 @@ nbdkit_SOURCES = \ connections.c \ crypto.c \ debug.c \ + extents.c \ filters.c \ internal.h \ locks.c \ diff --git a/server/nbdkit.syms b/server/nbdkit.syms index 672abd2..240953e 100644 --- a/server/nbdkit.syms +++ b/server/nbdkit.syms @@ -40,8 +40,13 @@ # The functions we want plugins and filters to call. global: nbdkit_absolute_path; + nbdkit_add_extent; nbdkit_debug; nbdkit_error; + nbdkit_extents_count; + nbdkit_extents_free; + nbdkit_extents_new; + nbdkit_get_extent; nbdkit_parse_bool; nbdkit_parse_size; nbdkit_read_password; -- 2.20.1

On Thu, Mar 28, 2019 at 09:24:25PM -0500, Eric Blake wrote: Yes - I think we got all the permissions back so I'll submit that change shortly. Yes it's an off-by-one error, so I'll fix it for both. I think if we do that we'll end up getting errors from filters (or complicating filters). It seems to be valid for a filter to want to query the extents of a zero-sized slice of a plugin, even though from a quick examination I don't think any existing filters do that today. If we allow zero sized ranges then is that true? If zero sized ranges are disallowed then I agree we could check for that. Yes, I'll update the comment. I should note that if we stored some kind of "last position" then we could check for API violations in all cases I think. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top

Provides automatic cleanup of ‘struct nbdkit_extents_map *’ on exit from a scope or function. --- server/internal.h | 2 ++ server/cleanup.c | 8 +++++++- server/Makefile.am | 3 ++- 3 files changed, 11 insertions(+), 2 deletions(-) diff --git a/server/internal.h b/server/internal.h index 71d2815..ae51804 100644 --- a/server/internal.h +++ b/server/internal.h @@ -139,6 +139,8 @@ extern void change_user (void); /* cleanup.c */ extern void cleanup_free (void *ptr); #define CLEANUP_FREE __attribute__((cleanup (cleanup_free))) +extern void cleanup_extents_free (void *ptr); +#define CLEANUP_EXTENTS_FREE __attribute__((cleanup (cleanup_extents_free))) extern void cleanup_unlock (pthread_mutex_t **ptr); #define CLEANUP_UNLOCK __attribute__((cleanup (cleanup_unlock))) #define ACQUIRE_LOCK_FOR_CURRENT_SCOPE(mutex) \ diff --git a/server/cleanup.c b/server/cleanup.c index c29ecec..1eec613 100644 --- a/server/cleanup.c +++ b/server/cleanup.c @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2013-2018 Red Hat Inc. + * Copyright (C) 2013-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -46,6 +46,12 @@ cleanup_free (void *ptr) free (* (void **) ptr); } +void +cleanup_extents_free (void *ptr) +{ + nbdkit_extents_free (* (void **) ptr); +} + void cleanup_unlock (pthread_mutex_t **ptr) { diff --git a/server/Makefile.am b/server/Makefile.am index 5ee662e..d50ebe4 100644 --- a/server/Makefile.am +++ b/server/Makefile.am @@ -125,7 +125,8 @@ check_PROGRAMS = test-utils test_utils_SOURCES = \ test-utils.c \ utils.c \ - cleanup.c + cleanup.c \ + extents.c test_utils_CPPFLAGS = \ -I$(top_srcdir)/include \ -I$(top_srcdir)/common/include -- 2.20.1

--- filters/blocksize/nbdkit-blocksize-filter.pod | 4 ++-- filters/blocksize/blocksize.c | 19 +++++++++++++++++++ 2 files changed, 21 insertions(+), 2 deletions(-) diff --git a/filters/blocksize/nbdkit-blocksize-filter.pod b/filters/blocksize/nbdkit-blocksize-filter.pod index b6cf4dd..0abed2f 100644 --- a/filters/blocksize/nbdkit-blocksize-filter.pod +++ b/filters/blocksize/nbdkit-blocksize-filter.pod @@ -56,8 +56,8 @@ of 1024. =item B<maxlen=>SIZE -The maximum length for any single transaction without data (trim and -zero). If omitted, this defaults to 0xffffffff rounded down to +The maximum length for any single transaction without data (trim, zero +or extents). If omitted, this defaults to 0xffffffff rounded down to C<minsize> alignment (that is, the inherent 32-bit limit of the NBD protocol). This need not be a power of two, but must be an integer multiple of C<minblock>, and should be at least as large as diff --git a/filters/blocksize/blocksize.c b/filters/blocksize/blocksize.c index 9e0e713..55b2d59 100644 --- a/filters/blocksize/blocksize.c +++ b/filters/blocksize/blocksize.c @@ -45,6 +45,7 @@ #include <nbdkit-filter.h> #include "minmax.h" +#include "rounding.h" /* XXX See design comment in filters/cow/cow.c. */ #define THREAD_MODEL NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS @@ -372,6 +373,23 @@ blocksize_zero (struct nbdkit_next_ops *next_ops, void *nxdata, return 0; } +static int +blocksize_extents (struct nbdkit_next_ops *next_ops, void *nxdata, + void *handle, uint32_t count, uint64_t offset, + uint32_t flags, struct nbdkit_extents *extents, int *err) +{ + /* Ask the plugin for blocksize-aligned data. Since the extents + * list start is set to the real offset, everything before the + * offset is ignored automatically. Also we only need to ask for + * maxlen of data, because it's fine to return less than the full + * count as long as we're making progress. + */ + return next_ops->extents (nxdata, + MIN (count, maxlen), + ROUND_DOWN (offset, minblock), + flags, extents, err); +} + static struct nbdkit_filter filter = { .name = "blocksize", .longname = "nbdkit blocksize filter", @@ -386,6 +404,7 @@ static struct nbdkit_filter filter = { .pwrite = blocksize_pwrite, .trim = blocksize_trim, .zero = blocksize_zero, + .extents = blocksize_extents, }; NBDKIT_REGISTER_FILTER(filter) -- 2.20.1

The cow filter doesn't support trimming and we should assume the underlying plugin is fully allocated too. Note that both of these limitations might be lifted with a more advanced filter implementation. --- filters/cow/cow.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/filters/cow/cow.c b/filters/cow/cow.c index b8f08c4..570a65f 100644 --- a/filters/cow/cow.c +++ b/filters/cow/cow.c @@ -114,7 +114,7 @@ cow_prepare (struct nbdkit_next_ops *next_ops, void *nxdata, } /* Whatever the underlying plugin can or can't do, we can write, we - * cannot trim, and we can flush. + * cannot trim or detect extents, and we can flush. */ static int cow_can_write (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle) @@ -128,6 +128,12 @@ cow_can_trim (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle) return 0; } +static int +cow_can_extents (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle) +{ + return 0; +} + static int cow_can_flush (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle) { @@ -316,6 +322,7 @@ static struct nbdkit_filter filter = { .can_write = cow_can_write, .can_flush = cow_can_flush, .can_trim = cow_can_trim, + .can_extents = cow_can_extents, .can_fua = cow_can_fua, .pread = cow_pread, .pwrite = cow_pwrite, -- 2.20.1

--- filters/error/nbdkit-error-filter.pod | 11 ++++++-- filters/error/error.c | 36 ++++++++++++++++++++++++--- 2 files changed, 41 insertions(+), 6 deletions(-) diff --git a/filters/error/nbdkit-error-filter.pod b/filters/error/nbdkit-error-filter.pod index 504e1b0..16ef184 100644 --- a/filters/error/nbdkit-error-filter.pod +++ b/filters/error/nbdkit-error-filter.pod @@ -12,6 +12,7 @@ nbdkit-error-filter - inject errors for testing clients [error-pwrite=...] [error-pwrite-rate=...] [error-pwrite-file=...] [error-trim=...] [error-trim-rate=...] [error-trim-file=...] [error-zero=...] [error-zero-rate=...] [error-zero-file=...] + [error-extents=...] [error-extents-rate=...] [error-extents-file=...] =head1 DESCRIPTION @@ -29,8 +30,9 @@ Inject a low rate of errors randomly into the connection: nbdkit --filter=error file disk.img error-rate=1% -Reading and trimming requests will be successful, but all -writes and zeroing will return "No space left on device": +Reading, trimming and extents (block status) requests will be +successful, but all writes and zeroing will return "No space left on +device": nbdkit --filter=error file disk.img \ error=ENOSPC \ @@ -105,6 +107,11 @@ settings to NBD trim requests. Same as C<error>, C<error-rate> and C<error-file> but only apply the settings to NBD zero requests. +=item B<error-extents>, B<error-extents-rate>, B<error-extents-file>. + +Same as C<error>, C<error-rate> and C<error-file> but only apply the +settings to NBD block status requests to read extents. + =back =head1 NOTES diff --git a/filters/error/error.c b/filters/error/error.c index 598bd1f..405bbe3 100644 --- a/filters/error/error.c +++ b/filters/error/error.c @@ -63,6 +63,7 @@ static struct error_settings pread_settings = ERROR_DEFAULT; static struct error_settings pwrite_settings = ERROR_DEFAULT; static struct error_settings trim_settings = ERROR_DEFAULT; static struct error_settings zero_settings = ERROR_DEFAULT; +static struct error_settings extents_settings = ERROR_DEFAULT; /* Random state. * This must only be accessed when holding the lock (except for load). @@ -83,6 +84,7 @@ error_unload (void) free (pwrite_settings.file); free (trim_settings.file); free (zero_settings.file); + free (extents_settings.file); } static const struct { const char *name; int error; } errors[] = { @@ -162,7 +164,8 @@ error_config (nbdkit_next_config *next, void *nxdata, if (parse_error (key, value, &i) == -1) return -1; pread_settings.error = pwrite_settings.error = - trim_settings.error = zero_settings.error = i; + trim_settings.error = zero_settings.error = + extents_settings.error = i; return 0; } else if (strcmp (key, "error-pread") == 0) @@ -173,12 +176,15 @@ error_config (nbdkit_next_config *next, void *nxdata, return parse_error (key, value, &trim_settings.error); else if (strcmp (key, "error-zero") == 0) return parse_error (key, value, &zero_settings.error); + else if (strcmp (key, "error-extents") == 0) + return parse_error (key, value, &extents_settings.error); else if (strcmp (key, "error-rate") == 0) { if (parse_error_rate (key, value, &d) == -1) return -1; pread_settings.rate = pwrite_settings.rate = - trim_settings.rate = zero_settings.rate = d; + trim_settings.rate = zero_settings.rate = + extents_settings.rate = d; return 0; } else if (strcmp (key, "error-pread-rate") == 0) @@ -189,6 +195,8 @@ error_config (nbdkit_next_config *next, void *nxdata, return parse_error_rate (key, value, &trim_settings.rate); else if (strcmp (key, "error-zero-rate") == 0) return parse_error_rate (key, value, &zero_settings.rate); + else if (strcmp (key, "error-extents-rate") == 0) + return parse_error_rate (key, value, &extents_settings.rate); /* NB: We are using nbdkit_absolute_path here because the trigger * file probably doesn't exist yet. @@ -202,6 +210,8 @@ error_config (nbdkit_next_config *next, void *nxdata, trim_settings.file = nbdkit_absolute_path (value); free (zero_settings.file); zero_settings.file = nbdkit_absolute_path (value); + free (extents_settings.file); + extents_settings.file = nbdkit_absolute_path (value); return 0; } else if (strcmp (key, "error-pread-rate") == 0) { @@ -224,6 +234,11 @@ error_config (nbdkit_next_config *next, void *nxdata, zero_settings.file = nbdkit_absolute_path (value); return 0; } + else if (strcmp (key, "error-extents-rate") == 0) { + free (extents_settings.file); + extents_settings.file = nbdkit_absolute_path (value); + return 0; + } else return next (nxdata, key, value); @@ -234,8 +249,8 @@ error_config (nbdkit_next_config *next, void *nxdata, " The error indication to return.\n" \ "error-rate=0%..100%|0..1 Rate of errors to generate.\n" \ "error-file=TRIGGER Set trigger filename.\n" \ - "error-pread*, error-pwrite*, error-trim*, error-zero*\n" \ - " Apply settings only to read/write/trim/zero" + "error-pread*, error-pwrite*, error-trim*, error-zero*, error-extents*\n" \ + " Apply settings only to read/write/etc" static void * error_open (nbdkit_next_open *next, void *nxdata, int readonly) @@ -330,6 +345,18 @@ error_zero (struct nbdkit_next_ops *next_ops, void *nxdata, return next_ops->zero (nxdata, count, offset, flags, err); } +/* Extents. */ +static int +error_extents (struct nbdkit_next_ops *next_ops, void *nxdata, + void *handle, uint32_t count, uint64_t offset, + uint32_t flags, struct nbdkit_extents *extents, int *err) +{ + if (random_error (&extents_settings, "extents", err)) + return -1; + + return next_ops->extents (nxdata, count, offset, flags, extents, err); +} + static struct nbdkit_filter filter = { .name = "error", .longname = "nbdkit error filter", @@ -343,6 +370,7 @@ static struct nbdkit_filter filter = { .pwrite = error_pwrite, .trim = error_trim, .zero = error_zero, + .extents = error_extents, }; NBDKIT_REGISTER_FILTER(filter) -- 2.20.1

Typical output: 2019-03-26 18:22:17.287434 connection=2 Extents id=2 offset=0x0 count=0x40000000 req_one=1 ... 2019-03-26 18:22:17.290040 connection=2 ...Extents id=2 extents=[{ offset=0x0, length=0x250000, type=0 }, { offset=0x250000, length=0x7db0000, type=3 }, { offset=0x8000000, length=0x8000, type=0 }, { offset=0x8008000, length=0x38000, type=3 }, { offset=0x8040000, length=0x208000, type=0 }, { offset=0x8248000, length=0x7db8000, type=3 }, { offset=0x10000000, length=0x208000, type=0 }, { offset=0x10208000, length=0x7df8000, type=3 }, { offset=0x18000000, length=0x8000, type=0 }, { offset=0x18008000, length=0x38000, type=3 }, { offset=0x18040000, length=0x208000, type=0 }, { offset=0x18248000, length=0x7db8000, type=3 }, { offset=0x20000000, length=0x208000, type=0 }, { offset=0x20208000, length=0x7df8000, type=3 }, { offset=0x28000000, length=0x8000, type=0 }, { offset=0x28008000, length=0x38000, type=3 }, { offset=0x28040000, length=0x208000, type=0 }, { offset=0x28248000, length=0x7db8000, type=3 }, { offset=0x30000000, length=0x208000, type=0 }, { offset=0x30208000, length=0x7df8000, type=3 }, { offset=0x38000000, length=0x8000, type=0 }, { offset=0x38008000, length=0x38000, type=3 }, { offset=0x38040000, length=0x208000, type=0 }, { offset=0x38248000, length=0x7da8000, type=3 }, { offset=0x3fff0000, length=0x10000, type=0 }] return=0 As you can see this is logging the complete information as generated by the underlying plugin, not what is returned to the client (which is rather hard for the log filter to discern). It's probably more useful for debugging like this. --- filters/log/nbdkit-log-filter.pod | 6 ++--- filters/log/log.c | 45 +++++++++++++++++++++++++++++++ 2 files changed, 48 insertions(+), 3 deletions(-) diff --git a/filters/log/nbdkit-log-filter.pod b/filters/log/nbdkit-log-filter.pod index cff209e..e391046 100644 --- a/filters/log/nbdkit-log-filter.pod +++ b/filters/log/nbdkit-log-filter.pod @@ -46,9 +46,9 @@ the impact of the caching. This filter writes to the file specified by the C<logfile=FILE> parameter. All lines include a timestamp, a connection counter, then details about the command. The following actions are logged: Connect, -Read, Write, Zero, Trim, Flush, and Disconnect. Except for Connect -and Disconnect, an event is logged across two lines for call and -return value, to allow tracking duration and tracing any parallel +Read, Write, Zero, Trim, Extents, Flush, and Disconnect. Except for +Connect and Disconnect, an event is logged across two lines for call +and return value, to allow tracking duration and tracing any parallel execution, using id for correlation (incremented per action on the connection). diff --git a/filters/log/log.c b/filters/log/log.c index 9f2e37d..b31d784 100644 --- a/filters/log/log.c +++ b/filters/log/log.c @@ -353,6 +353,50 @@ log_zero (struct nbdkit_next_ops *next_ops, void *nxdata, return r; } +/* Extents. */ +static int +log_extents (struct nbdkit_next_ops *next_ops, void *nxdata, + void *handle, uint32_t count, uint64_t offs, uint32_t flags, + struct nbdkit_extents *extents, int *err) +{ + struct handle *h = handle; + uint64_t id = get_id (h); + int r; + + assert (!(flags & ~(NBDKIT_FLAG_REQ_ONE))); + output (h, "Extents", id, + "offset=0x%" PRIx64 " count=0x%x req_one=%d ...", + offs, count, !!(flags & NBDKIT_FLAG_REQ_ONE)); + r = next_ops->extents (nxdata, count, offs, flags, extents, err); + if (r == -1) + output_return (h, "...Extents", id, r, err); + else { + FILE *fp; + char *extents_str = NULL; + size_t i, n, len = 0; + + fp = open_memstream (&extents_str, &len); + if (fp != NULL) { + n = nbdkit_extents_count (extents); + for (i = 0; i < n; ++i) { + struct nbdkit_extent e = nbdkit_get_extent (extents, i); + if (i > 0) + fprintf (fp, ", "); + fprintf (fp, "{ offset=0x%" PRIx64 ", length=0x%" PRIx64 ", " + "type=%" PRIu32 " }", + e.offset, e.length, e.type); + } + + fclose (fp); + } + + output (h, "...Extents", id, "extents=[%s] return=0", + extents_str ? extents_str : "(null)"); + free (extents_str); + } + return r; +} + static struct nbdkit_filter filter = { .name = "log", .longname = "nbdkit log filter", @@ -370,6 +414,7 @@ static struct nbdkit_filter filter = { .flush = log_flush, .trim = log_trim, .zero = log_zero, + .extents = log_extents, }; NBDKIT_REGISTER_FILTER(filter) -- 2.20.1

On 3/28/19 11:18 AM, Richard W.M. Jones wrote: Missed a change to log_prepare() so that the log will include results of .can_extents. I've pushed the obvious fix. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org

--- filters/partition/partition.c | 37 +++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/filters/partition/partition.c b/filters/partition/partition.c index c1fe7a1..bc60480 100644 --- a/filters/partition/partition.c +++ b/filters/partition/partition.c @@ -38,6 +38,7 @@ #include <stdint.h> #include <string.h> #include <inttypes.h> +#include <assert.h> #include <nbdkit-filter.h> @@ -222,6 +223,41 @@ partition_zero (struct nbdkit_next_ops *next_ops, void *nxdata, return next_ops->zero (nxdata, count, offs + h->offset, flags, err); } +/* Extents. */ +static int +partition_extents (struct nbdkit_next_ops *next_ops, void *nxdata, + void *handle, uint32_t count, uint64_t offs, uint32_t flags, + struct nbdkit_extents *extents, int *err) +{ + struct handle *h = handle; + size_t i; + struct nbdkit_extents *extents2; + struct nbdkit_extent e; + int64_t real_size = next_ops->get_size (nxdata); + + extents2 = nbdkit_extents_new (offs + h->offset, real_size - h->offset); + if (extents2 == NULL) { + *err = errno; + return -1; + } + if (next_ops->extents (nxdata, count, offs + h->offset, + flags, extents2, err) == -1) + goto error; + + for (i = 0; i < nbdkit_extents_count (extents2); ++i) { + e = nbdkit_get_extent (extents2, i); + e.offset -= h->offset; + if (nbdkit_add_extent (extents, e.offset, e.length, e.type) == -1) + goto error; + } + nbdkit_extents_free (extents2); + return 0; + + error: + nbdkit_extents_free (extents2); + return -1; +} + static struct nbdkit_filter filter = { .name = "partition", .longname = "nbdkit partition filter", @@ -237,6 +273,7 @@ static struct nbdkit_filter filter = { .pwrite = partition_pwrite, .trim = partition_trim, .zero = partition_zero, + .extents = partition_extents, }; NBDKIT_REGISTER_FILTER(filter) -- 2.20.1

On Mon, Apr 01, 2019 at 01:42:47PM +0200, Martin Kletzander wrote: This was a mistake - I've pushed a patch to remove both instances. Thanks, Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top

These plugins are both based on the same sparse array structure which supports a simple implementation of extents. --- common/sparse/sparse.h | 7 +- common/sparse/sparse.c | 37 ++++++++++- plugins/data/data.c | 16 ++++- plugins/memory/memory.c | 16 ++++- README | 2 + tests/Makefile.am | 2 + tests/test-data-extents.sh | 131 +++++++++++++++++++++++++++++++++++++ 7 files changed, 207 insertions(+), 4 deletions(-) diff --git a/common/sparse/sparse.h b/common/sparse/sparse.h index 818d804..eb24a0b 100644 --- a/common/sparse/sparse.h +++ b/common/sparse/sparse.h @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2017-2018 Red Hat Inc. + * Copyright (C) 2017-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -87,4 +87,9 @@ extern void sparse_array_zero (struct sparse_array *sa, uint32_t count, uint64_t offset) __attribute__((__nonnull__ (1))); +/* Return information about allocated pages and holes. */ +extern int sparse_array_extents (struct sparse_array *sa, + uint32_t count, uint64_t offset, + struct nbdkit_extents *extents); + #endif /* NBDKIT_SPARSE_H */ diff --git a/common/sparse/sparse.c b/common/sparse/sparse.c index a5ace48..d5654c2 100644 --- a/common/sparse/sparse.c +++ b/common/sparse/sparse.c @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2017-2018 Red Hat Inc. + * Copyright (C) 2017-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -360,3 +360,38 @@ sparse_array_zero (struct sparse_array *sa, uint32_t count, uint64_t offset) offset += n; } } + +int +sparse_array_extents (struct sparse_array *sa, + uint32_t count, uint64_t offset, + struct nbdkit_extents *extents) +{ + uint32_t n, type; + void *p; + + while (count > 0) { + p = lookup (sa, offset, false, &n, NULL); + if (n > count) + n = count; + + /* Work out the type of this extent. */ + if (p == NULL) + /* No backing page, so it's a hole. */ + type = NBDKIT_EXTENT_HOLE | NBDKIT_EXTENT_ZERO; + else { + if (is_zero (p, n)) + /* A backing page and it's all zero, it's a zero extent. */ + type = NBDKIT_EXTENT_ZERO; + else + /* Normal allocated data. */ + type = 0; + } + if (nbdkit_add_extent (extents, offset, n, type) == -1) + return -1; + + count -= n; + offset += n; + } + + return 0; +} diff --git a/plugins/data/data.c b/plugins/data/data.c index f9d3881..c5540f6 100644 --- a/plugins/data/data.c +++ b/plugins/data/data.c @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2018 Red Hat Inc. + * Copyright (C) 2018-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -378,6 +378,19 @@ data_trim (void *handle, uint32_t count, uint64_t offset) return 0; } +/* Extents. */ +static int +data_extents (void *handle, uint32_t count, uint64_t offset, + uint32_t flags, struct nbdkit_extents *extents) +{ + int r; + + pthread_mutex_lock (&lock); + r = sparse_array_extents (sa, count, offset, extents); + pthread_mutex_unlock (&lock); + return r; +} + static struct nbdkit_plugin plugin = { .name = "data", .version = PACKAGE_VERSION, @@ -394,6 +407,7 @@ static struct nbdkit_plugin plugin = { .pwrite = data_pwrite, .zero = data_zero, .trim = data_trim, + .extents = data_extents, /* In this plugin, errno is preserved properly along error return * paths from failed system calls. */ diff --git a/plugins/memory/memory.c b/plugins/memory/memory.c index e27e127..741eaad 100644 --- a/plugins/memory/memory.c +++ b/plugins/memory/memory.c @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2017-2018 Red Hat Inc. + * Copyright (C) 2017-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -170,6 +170,19 @@ memory_trim (void *handle, uint32_t count, uint64_t offset) return 0; } +/* Extents. */ +static int +memory_extents (void *handle, uint32_t count, uint64_t offset, + uint32_t flags, struct nbdkit_extents *extents) +{ + int r; + + pthread_mutex_lock (&lock); + r = sparse_array_extents (sa, count, offset, extents); + pthread_mutex_unlock (&lock); + return r; +} + static struct nbdkit_plugin plugin = { .name = "memory", .version = PACKAGE_VERSION, @@ -185,6 +198,7 @@ static struct nbdkit_plugin plugin = { .pwrite = memory_pwrite, .zero = memory_zero, .trim = memory_trim, + .extents = memory_extents, /* In this plugin, errno is preserved properly along error return * paths from failed system calls. */ diff --git a/README b/README index 75230c9..497f4fd 100644 --- a/README +++ b/README @@ -152,6 +152,8 @@ To test for memory leaks (‘make check-valgrind’): For non-essential enhancements to the test suite: + - jq + - ip, ss (from iproute package) - losetup (from util-linux package) diff --git a/tests/Makefile.am b/tests/Makefile.am index dec44b5..174da29 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -53,6 +53,7 @@ EXTRA_DIST = \ test-cxx.sh \ test-data-7E.sh \ test-data-base64.sh \ + test-data-extents.sh \ test-data-file.sh \ test-data-raw.sh \ test-debug-flags.sh \ @@ -372,6 +373,7 @@ LIBGUESTFS_TESTS += test-data TESTS += \ test-data-7E.sh \ test-data-base64.sh \ + test-data-extents.sh \ test-data-file.sh \ test-data-raw.sh diff --git a/tests/test-data-extents.sh b/tests/test-data-extents.sh new file mode 100755 index 0000000..2b25bde --- /dev/null +++ b/tests/test-data-extents.sh @@ -0,0 +1,131 @@ +#!/usr/bin/env bash +# nbdkit +# Copyright (C) 2018-2019 Red Hat Inc. +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are +# met: +# +# * Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# +# * Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution. +# +# * Neither the name of Red Hat nor the names of its contributors may be +# used to endorse or promote products derived from this software without +# specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND +# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, +# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A +# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR +# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF +# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT +# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +# SUCH DAMAGE. + +# Unfortunately the output of this test depends on the PAGE_SIZE +# defined in common/sparse/sparse.c and would change (breaking the +# test) if we ever changed that definition. + +source ./functions.sh +set -e +set -x + +requires jq --version +requires qemu-img --version +requires qemu-img map --help + +out="test-data-extents.out" +expected="test-data-extents.expected" +files="$out $expected" +rm -f $files +cleanup_fn rm -f $files + +do_test () +{ + # We use jq to normalize the output and convert it to plain text. + nbdkit -U - data data="$1" size="$2" \ + --run 'qemu-img map -f raw --output=json $nbd' | + jq -c '.[] | {start:.start, length:.length, data:.data, zero:.zero}' \ + > $out + if ! cmp $out $expected; then + echo "$0: output did not match expected data" + echo "expected:" + cat $expected + echo "output:" + cat $out + exit 1 + fi +} + +# Completely sparse disk. +cat > $expected <<'EOF' +{"start":0,"length":1048576,"data":false,"zero":true} +EOF +do_test "" 1M + +# Completely allocated disk. +cat > $expected <<'EOF' +{"start":0,"length":32768,"data":true,"zero":false} +EOF +do_test "1" 32K + +# Allocated data at the start of a 1M disk. +cat > $expected <<'EOF' +{"start":0,"length":32768,"data":true,"zero":false} +{"start":32768,"length":1015808,"data":false,"zero":true} +EOF +do_test "1" 1M + +# Allocated zeroes at the start of the disk. This should create a +# zero extent (data=true zero=true). +cat > $expected <<'EOF' +{"start":0,"length":32768,"data":true,"zero":true} +{"start":32768,"length":1015808,"data":false,"zero":true} +EOF +do_test "0" 1M + +# Completely zero disk. +cat > $expected <<'EOF' +{"start":0,"length":32768,"data":true,"zero":true} +EOF +do_test "0 0 0" 32K + +# Allocated data and zero extents in a few places in the middle. +cat > $expected <<'EOF' +{"start":0,"length":32768,"data":false,"zero":true} +{"start":32768,"length":32768,"data":true,"zero":false} +{"start":65536,"length":32768,"data":true,"zero":true} +{"start":98304,"length":32768,"data":false,"zero":true} +{"start":131072,"length":32768,"data":true,"zero":false} +{"start":163840,"length":98304,"data":false,"zero":true} +{"start":262144,"length":32768,"data":true,"zero":true} +{"start":294912,"length":32768,"data":true,"zero":false} +{"start":327680,"length":720896,"data":false,"zero":true} +EOF +do_test "@32768 1 @65536 0 @131072 1 @262144 0 @294912 1" 1M + +# This should test coalescing in the extents code. +cat > $expected <<'EOF' +{"start":0,"length":32768,"data":false,"zero":true} +{"start":32768,"length":65536,"data":true,"zero":false} +{"start":98304,"length":32768,"data":false,"zero":true} +{"start":131072,"length":65536,"data":true,"zero":true} +{"start":196608,"length":851968,"data":false,"zero":true} +EOF +do_test "@32768 1 @65536 1 @131072 0 @163840 0" 1M + +# Zero-length plugin. Unlike nbdkit-zero-plugin, the data plugin +# advertises extents and so will behave differently. +cat > $expected <<'EOF' +{"start":0,"length":0,"data":false,"zero":false} +EOF +do_test "" 0 -- 2.20.1

On Tue, Apr 23, 2019 at 07:59:52PM -0500, Eric Blake wrote: We can't use qemu-img map to print the extents information that the plugin returns, but we can use the log filter: $ ./nbdkit -fv --filter=log \ data data="1" size=512 logfile=/dev/stdout \ --run 'qemu-img convert -n $nbd null-co://' |& grep Extents 2019-04-24 11:12:25.664206 connection=1 Extents id=2 offset=0x0 count=0x200 req_one=1 ... 2019-04-24 11:12:25.664302 connection=1 ...Extents id=2 extents=[{ offset=0x0, length=0x200, hole=0, zero=0 }] return=0 Therefore I'll declare that in this case the problem above of overlong extents information is fixed. I believe that was fixed when we rewrote nbdkit_extents_new to take an ‘end’ parameter in the final version of commit 4ca66f70a5. $ ./nbdkit -fv --filter=log --filter=truncate \ data data="1" size=512 truncate=64K logfile=/dev/stdout \ --run 'qemu-img convert -n $nbd null-co://' |& grep Extents 2019-04-24 11:17:31.618246 connection=1 Extents id=2 offset=0x0 count=0x10000 req_one=1 ... 2019-04-24 11:17:31.618371 connection=1 ...Extents id=2 extents=[{ offset=0x0, length=0x200, hole=0, zero=0 }] return=0 2019-04-24 11:17:31.659589 connection=1 Extents id=3 offset=0x200 count=0xfe00 req_one=1 ... 2019-04-24 11:17:31.659674 connection=1 ...Extents id=3 extents=[{ offset=0x200, length=0xfe00, hole=1, zero=1 }] return=0 It is now returning: [length=0x200, type=data] [offset=0x200, length=0xfe00, type=hole|zero] which looks correct to me. I moved the clamp as originally suggested in your email here: https://www.redhat.com/archives/libguestfs/2019-March/msg00126.html The output from the commands above is the same and the tests pass. Patch is below. Rich. From: "Richard W.M. Jones" <rjones(a)redhat.com&gt; Date: Wed, 24 Apr 2019 12:24:07 +0100 Subject: [PATCH] common/sparse: Return the maximum amount of information about sparseness. By moving the clamp we can return more information about sparseness that we have but which was not requested. This is permitted and can improve the efficiency of clients. See: https://www.redhat.com/archives/libguestfs/2019-April/msg00192.html Thanks: Eric Blake. --- common/sparse/sparse.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/common/sparse/sparse.c b/common/sparse/sparse.c index b46bd31..cb44743 100644 --- a/common/sparse/sparse.c +++ b/common/sparse/sparse.c @@ -370,8 +370,6 @@ sparse_array_extents (struct sparse_array *sa, while (count > 0) { p = lookup (sa, offset, false, &n, NULL); - if (n > count) - n = count; /* Work out the type of this extent. */ if (p == NULL) @@ -388,6 +386,9 @@ sparse_array_extents (struct sparse_array *sa, if (nbdkit_add_extent (extents, offset, n, type) == -1) return -1; + if (n > count) + n = count; + count -= n; offset += n; } -- 2.20.1 -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/

This uses lseek SEEK_DATA/SEEK_HOLE to search for allocated data and holes in the underlying file. --- plugins/file/file.c | 141 ++++++++++++++++++++++++++++++++++--- tests/Makefile.am | 5 ++ tests/test-file-extents.sh | 57 +++++++++++++++ 3 files changed, 193 insertions(+), 10 deletions(-) diff --git a/plugins/file/file.c b/plugins/file/file.c index 628f8fb..2fbc2a3 100644 --- a/plugins/file/file.c +++ b/plugins/file/file.c @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2013-2018 Red Hat Inc. + * Copyright (C) 2013-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -37,6 +37,7 @@ #include <stdlib.h> #include <stdbool.h> #include <string.h> +#include <inttypes.h> #include <fcntl.h> #include <unistd.h> #include <sys/types.h> @@ -44,6 +45,8 @@ #include <sys/ioctl.h> #include <errno.h> +#include <pthread.h> + #if defined(__linux__) && !defined(FALLOC_FL_PUNCH_HOLE) #include <linux/falloc.h> /* For FALLOC_FL_*, glibc < 2.18 */ #endif @@ -68,7 +71,11 @@ static char *filename = NULL; -int file_debug_zero; /* to enable: -D file.zero=1 */ +/* Any callbacks using lseek must be protected by this lock. */ +static pthread_mutex_t lseek_lock = PTHREAD_MUTEX_INITIALIZER; + +/* to enable: -D file.zero=1 */ +int file_debug_zero; static void file_unload (void) @@ -220,6 +227,23 @@ file_close (void *handle) #define THREAD_MODEL NBDKIT_THREAD_MODEL_PARALLEL +/* For block devices, stat->st_size is not the true size. The caller + * grabs the lseek_lock. + */ +static int64_t +block_device_size (int fd) +{ + off_t size; + + size = lseek (fd, 0, SEEK_END); + if (size == -1) { + nbdkit_error ("lseek (to find device size): %m"); + return -1; + } + + return size; +} + /* Get the file size. */ static int64_t file_get_size (void *handle) @@ -227,15 +251,11 @@ file_get_size (void *handle) struct handle *h = handle; if (h->is_block_device) { - /* Block device, so st_size will not be the true size. */ - off_t size; - - size = lseek (h->fd, 0, SEEK_END); - if (size == -1) { - nbdkit_error ("lseek (to find device size): %m"); - return -1; - } + int64_t size; + pthread_mutex_lock (&lseek_lock); + size = block_device_size (h->fd); + pthread_mutex_unlock (&lseek_lock); return size; } else { /* Regular file. */ @@ -501,6 +521,103 @@ file_trim (void *handle, uint32_t count, uint64_t offset, uint32_t flags) return 0; } +#ifdef SEEK_HOLE +/* Extents. */ + +static int +file_can_extents (void *handle) +{ + struct handle *h = handle; + off_t r; + + /* A simple test to see whether SEEK_HOLE etc is likely to work on + * the current filesystem. + */ + pthread_mutex_lock (&lseek_lock); + r = lseek (h->fd, 0, SEEK_HOLE); + pthread_mutex_unlock (&lseek_lock); + if (r == -1) { + nbdkit_debug ("extents disabled: lseek: SEEK_HOLE: %m"); + return 0; + } + return 1; +} + +static int +do_extents (void *handle, uint32_t count, uint64_t offset, + uint32_t flags, struct nbdkit_extents *extents) +{ + struct handle *h = handle; + const bool req_one = flags & NBDKIT_FLAG_REQ_ONE; + uint64_t end = offset + count; + + do { + off_t pos; + + pos = lseek (h->fd, offset, SEEK_DATA); + if (pos == -1) { + if (errno == ENXIO) { + /* The current man page does not describe this situation well, + * but a proposed change to POSIX adds these words for ENXIO: + * "or the whence argument is SEEK_DATA and the offset falls + * within the final hole of the file." + */ + pos = end; + } + else { + nbdkit_error ("lseek: SEEK_DATA: %" PRIu64 ": %m", offset); + return -1; + } + } + + /* We know there is a hole from offset to pos-1. */ + if (pos > offset) { + if (nbdkit_add_extent (extents, offset, pos - offset, + NBDKIT_EXTENT_HOLE | NBDKIT_EXTENT_ZERO) == -1) + return -1; + if (req_one) + break; + } + + offset = pos; + if (offset >= end) + break; + + pos = lseek (h->fd, offset, SEEK_HOLE); + if (pos == -1) { + nbdkit_error ("lseek: SEEK_HOLE: %" PRIu64 ": %m", offset); + return -1; + } + + /* We know there is data from offset to pos-1. */ + if (pos > offset) { + if (nbdkit_add_extent (extents, offset, pos - offset, + 0 /* allocated data */) == -1) + return -1; + if (req_one) + break; + } + + offset = pos; + } while (offset < end); + + return 0; +} + +static int +file_extents (void *handle, uint32_t count, uint64_t offset, + uint32_t flags, struct nbdkit_extents *extents) +{ + int r; + + pthread_mutex_lock (&lseek_lock); + r = do_extents (handle, count, offset, flags, extents); + pthread_mutex_unlock (&lseek_lock); + + return r; +} +#endif /* SEEK_HOLE */ + static struct nbdkit_plugin plugin = { .name = "file", .longname = "nbdkit file plugin", @@ -522,6 +639,10 @@ static struct nbdkit_plugin plugin = { .flush = file_flush, .trim = file_trim, .zero = file_zero, +#ifdef SEEK_HOLE + .can_extents = file_can_extents, + .extents = file_extents, +#endif .errno_is_preserved = 1, }; diff --git a/tests/Makefile.am b/tests/Makefile.am index 174da29..64b2c45 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -64,6 +64,7 @@ EXTRA_DIST = \ test-error0.sh \ test-error10.sh \ test-error100.sh \ + test-file-extents.sh \ test-floppy.sh \ test-foreground.sh \ test-fua.sh \ @@ -419,6 +420,10 @@ test_file_block_SOURCES = test-file-block.c test.h test_file_block_CFLAGS = $(WARNINGS_CFLAGS) $(LIBGUESTFS_CFLAGS) test_file_block_LDADD = libtest.la $(LIBGUESTFS_LIBS) +if HAVE_GUESTFISH +TESTS += test-file-extents.sh +endif HAVE_GUESTFISH + # floppy plugin test. if HAVE_GUESTFISH TESTS += test-floppy.sh diff --git a/tests/test-file-extents.sh b/tests/test-file-extents.sh new file mode 100755 index 0000000..1f33c88 --- /dev/null +++ b/tests/test-file-extents.sh @@ -0,0 +1,57 @@ +#!/usr/bin/env bash +# nbdkit +# Copyright (C) 2018-2019 Red Hat Inc. +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are +# met: +# +# * Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# +# * Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution. +# +# * Neither the name of Red Hat nor the names of its contributors may be +# used to endorse or promote products derived from this software without +# specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND +# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, +# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A +# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR +# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF +# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT +# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +# SUCH DAMAGE. + +# The output of qemu-img map on the local sparse file ‘disk’ should be +# identical to the output when we use the file plugin to read the +# extents. + +source ./functions.sh +set -e +set -x + +requires jq --version +requires qemu-img --version +requires qemu-img map --help + +files="test-file-extents.out test-file-extents.expected" +rm -f $files +cleanup_fn rm -f $files + +qemu-img map -f raw --output=json disk | + jq -c '.[] | {start:.start, length:.length, data:.data, zero:.zero}' \ + > test-file-extents.out +nbdkit -U - file disk --run 'qemu-img map -f raw --output=json $nbd' | + jq -c '.[] | {start:.start, length:.length, data:.data, zero:.zero}' \ + > test-file-extents.expected + +diff -u test-file-extents.out test-file-extents.expected -- 2.20.1

This uses a new API VixDiskLib_QueryAllocatedBlocks provided in VDDK >= 6.7. Thanks: Martin Kletzander. --- plugins/vddk/vddk-structs.h | 15 +++- plugins/vddk/vddk.c | 169 ++++++++++++++++++++++++++++++++++++ 2 files changed, 183 insertions(+), 1 deletion(-) diff --git a/plugins/vddk/vddk-structs.h b/plugins/vddk/vddk-structs.h index dbed94a..df88322 100644 --- a/plugins/vddk/vddk-structs.h +++ b/plugins/vddk/vddk-structs.h @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2013-2018 Red Hat Inc. + * Copyright (C) 2013-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -47,6 +47,9 @@ typedef uint64_t VixError; #define VIXDISKLIB_FLAG_OPEN_READ_ONLY 4 #define VIXDISKLIB_SECTOR_SIZE 512 +#define VIXDISKLIB_MIN_CHUNK_SIZE 128 +#define VIXDISKLIB_MAX_CHUNK_NUMBER (512*1024) + typedef void *VixDiskLibConnection; typedef void *VixDiskLibHandle; @@ -124,4 +127,14 @@ typedef struct VixDiskLibInfo { char *uuid; } VixDiskLibInfo; +typedef struct { + uint64_t offset; + uint64_t length; +} VixDiskLibBlock; + +typedef struct { + uint32_t numBlocks; + VixDiskLibBlock blocks[1]; +} VixDiskLibBlockList; + #endif /* NBDKIT_VDDK_STRUCTS_H */ diff --git a/plugins/vddk/vddk.c b/plugins/vddk/vddk.c index 56871cc..56c5335 100644 --- a/plugins/vddk/vddk.c +++ b/plugins/vddk/vddk.c @@ -45,12 +45,17 @@ #include <nbdkit-plugin.h> #include "isaligned.h" +#include "minmax.h" +#include "rounding.h" #include "vddk-structs.h" /* Enable extra disk info debugging with: -D vddk.diskinfo=1 */ int vddk_debug_diskinfo; +/* Enable debugging of extents code with: -D vddk.extents=1 */ +int vddk_debug_extents; + /* The VDDK APIs that we call. These globals are initialized when the * plugin is loaded (by vddk_load). */ @@ -67,6 +72,8 @@ static VixError (*VixDiskLib_GetInfo) (VixDiskLibHandle handle, VixDiskLibInfo * static void (*VixDiskLib_FreeInfo) (VixDiskLibInfo *info); static VixError (*VixDiskLib_Read) (VixDiskLibHandle handle, uint64_t start_sector, uint64_t nr_sectors, unsigned char *buf); static VixError (*VixDiskLib_Write) (VixDiskLibHandle handle, uint64_t start_sector, uint64_t nr_sectors, const unsigned char *buf); +static VixError (*VixDiskLib_QueryAllocatedBlocks) (VixDiskLibHandle diskHandle, uint64_t start_sector, uint64_t nr_sectors, uint64_t chunk_size, VixDiskLibBlockList **block_list); +static VixError (*VixDiskLib_FreeBlockList) (VixDiskLibBlockList *block_list); /* Parameters passed to InitEx. */ #define VDDK_MAJOR 5 @@ -174,6 +181,11 @@ vddk_load (void) VixDiskLib_FreeInfo = dlsym (dl, "VixDiskLib_FreeInfo"); VixDiskLib_Read = dlsym (dl, "VixDiskLib_Read"); VixDiskLib_Write = dlsym (dl, "VixDiskLib_Write"); + + /* Added in VDDK 6.7, these will be NULL for earlier versions: */ + VixDiskLib_QueryAllocatedBlocks = + dlsym (dl, "VixDiskLib_QueryAllocatedBlocks"); + VixDiskLib_FreeBlockList = dlsym (dl, "VixDiskLib_FreeBlockList"); } static void @@ -570,6 +582,161 @@ vddk_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset) return 0; } +static int +vddk_can_extents (void *handle) +{ + struct vddk_handle *h = handle; + VixError err; + VixDiskLibBlockList *block_list; + + /* This call was added in VDDK 6.7. In earlier versions the + * function pointer will be NULL and we cannot query extents. + */ + if (VixDiskLib_QueryAllocatedBlocks == NULL) { + nbdkit_debug ("can_extents: VixDiskLib_QueryAllocatedBlocks == NULL, " + "probably this is VDDK < 6.7"); + return 0; + } + + /* However even when the call is available it rarely works well so + * the best thing we can do here is to try the call and if it's + * non-functional return false. + */ + DEBUG_CALL ("VixDiskLib_QueryAllocatedBlocks", + "handle, 0, %d sectors, %d sectors", + VIXDISKLIB_MIN_CHUNK_SIZE, VIXDISKLIB_MIN_CHUNK_SIZE); + err = VixDiskLib_QueryAllocatedBlocks (h->handle, + 0, VIXDISKLIB_MIN_CHUNK_SIZE, + VIXDISKLIB_MIN_CHUNK_SIZE, + &block_list); + if (err == VIX_OK) { + DEBUG_CALL ("VixDiskLib_FreeBlockList", "block_list"); + VixDiskLib_FreeBlockList (block_list); + } + if (err != VIX_OK) { + char *errmsg = VixDiskLib_GetErrorText (err, NULL); + nbdkit_debug ("can_extents: VixDiskLib_QueryAllocatedBlocks test failed, " + "extents support will be disabled: " + "original error: %s", + errmsg); + VixDiskLib_FreeErrorText (errmsg); + return 0; + } + + return 1; +} + +static int +add_extent (struct nbdkit_extents *extents, + uint64_t *position, uint64_t next_position, bool is_hole) +{ + const uint32_t type = is_hole ? NBDKIT_EXTENT_HOLE|NBDKIT_EXTENT_ZERO : 0; + const uint64_t length = next_position - *position; + + assert (*position <= next_position); + if (*position == next_position) + return 0; + + if (vddk_debug_extents) + nbdkit_debug ("adding extent type %s at [%" PRIu64 "...%" PRIu64 "]", + is_hole ? "hole" : "allocated data", + *position, next_position-1); + if (nbdkit_add_extent (extents, *position, length, type) == -1) + return -1; + + *position = next_position; + return 0; +} + +static int +vddk_extents (void *handle, uint32_t count, uint64_t offset, uint32_t flags, + struct nbdkit_extents *extents) +{ + struct vddk_handle *h = handle; + bool req_one = flags & NBDKIT_FLAG_REQ_ONE; + uint64_t position, end, start_sector; + + position = offset; + end = offset + count; + + /* We can only query whole chunks. Therefore start with the first + * chunk before offset. + */ + start_sector = + ROUND_DOWN (offset, VIXDISKLIB_MIN_CHUNK_SIZE * VIXDISKLIB_SECTOR_SIZE) + / VIXDISKLIB_SECTOR_SIZE; + while (start_sector * VIXDISKLIB_SECTOR_SIZE < end) { + VixError err; + uint32_t i; + uint64_t nr_chunks, nr_sectors; + VixDiskLibBlockList *block_list; + + assert (IS_ALIGNED (start_sector, VIXDISKLIB_MIN_CHUNK_SIZE)); + + nr_chunks = + ROUND_UP (end - start_sector * VIXDISKLIB_SECTOR_SIZE, + VIXDISKLIB_MIN_CHUNK_SIZE * VIXDISKLIB_SECTOR_SIZE) + / (VIXDISKLIB_MIN_CHUNK_SIZE * VIXDISKLIB_SECTOR_SIZE); + nr_chunks = MIN (nr_chunks, VIXDISKLIB_MAX_CHUNK_NUMBER); + nr_sectors = nr_chunks * VIXDISKLIB_MIN_CHUNK_SIZE; + + DEBUG_CALL ("VixDiskLib_QueryAllocatedBlocks", + "handle, %" PRIu64 " sectors, %" PRIu64 " sectors, " + "%d sectors", + start_sector, nr_sectors, VIXDISKLIB_MIN_CHUNK_SIZE); + err = VixDiskLib_QueryAllocatedBlocks (h->handle, + start_sector, nr_sectors, + VIXDISKLIB_MIN_CHUNK_SIZE, + &block_list); + if (err != VIX_OK) { + VDDK_ERROR (err, "VixDiskLib_QueryAllocatedBlocks"); + return -1; + } + + for (i = 0; i < block_list->numBlocks; ++i) { + uint64_t blk_offset, blk_length; + + blk_offset = block_list->blocks[i].offset * VIXDISKLIB_SECTOR_SIZE; + blk_length = block_list->blocks[i].length * VIXDISKLIB_SECTOR_SIZE; + + /* The query returns allocated blocks. We must insert holes + * between the blocks as necessary. + */ + if (position < blk_offset && + add_extent (extents, &position, blk_offset, true) == -1) + goto error_in_add; + if (add_extent (extents, + &position, blk_offset + blk_length, false) == -1) { + error_in_add: + DEBUG_CALL ("VixDiskLib_FreeBlockList", "block_list"); + VixDiskLib_FreeBlockList (block_list); + return -1; + } + } + DEBUG_CALL ("VixDiskLib_FreeBlockList", "block_list"); + VixDiskLib_FreeBlockList (block_list); + + /* There's an implicit hole after the returned list of blocks, up + * to the end of the QueryAllocatedBlocks request. + */ + if (add_extent (extents, + &position, + (start_sector + nr_sectors) * VIXDISKLIB_SECTOR_SIZE, + true) == -1) + return -1; + + start_sector += nr_sectors; + + /* If one extent was requested, as long as we've added an extent + * overlapping the original offset we're done. + */ + if (req_one && position > offset) + break; + } + + return 0; +} + static struct nbdkit_plugin plugin = { .name = "vddk", .longname = "VMware VDDK plugin", @@ -585,6 +752,8 @@ static struct nbdkit_plugin plugin = { .get_size = vddk_get_size, .pread = vddk_pread, .pwrite = vddk_pwrite, + .can_extents = vddk_can_extents, + .extents = vddk_extents, }; NBDKIT_REGISTER_PLUGIN(plugin) -- 2.20.1

Testing Block Status / extents is however rather more difficult, so this commit punts on it and just adds a comment to the code. --- tests/test-layers-filter.c | 21 +++++++++++++++++++++ tests/test-layers-plugin.c | 20 +++++++++++++++++++- tests/test-layers.c | 12 ++++++++++++ 3 files changed, 52 insertions(+), 1 deletion(-) diff --git a/tests/test-layers-filter.c b/tests/test-layers-filter.c index 6da6ee6..48ca8e6 100644 --- a/tests/test-layers-filter.c +++ b/tests/test-layers-filter.c @@ -176,6 +176,15 @@ test_layers_filter_can_multi_conn (struct nbdkit_next_ops *next_ops, return next_ops->can_multi_conn (nxdata); } +static int +test_layers_filter_can_extents (struct nbdkit_next_ops *next_ops, + void *nxdata, + void *handle) +{ + DEBUG_FUNCTION; + return next_ops->can_extents (nxdata); +} + static int test_layers_filter_pread (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle, void *buf, @@ -223,6 +232,16 @@ test_layers_filter_zero (struct nbdkit_next_ops *next_ops, void *nxdata, return next_ops->zero (nxdata, count, offset, flags, err); } +static int +test_layers_filter_extents (struct nbdkit_next_ops *next_ops, void *nxdata, + void *handle, uint32_t count, uint64_t offset, + uint32_t flags, struct nbdkit_extents *extents, + int *err) +{ + DEBUG_FUNCTION; + return next_ops->extents (nxdata, count, offset, flags, extents, err); +} + static struct nbdkit_filter filter = { .name = "testlayers" layer, .version = PACKAGE_VERSION, @@ -243,11 +262,13 @@ static struct nbdkit_filter filter = { .can_zero = test_layers_filter_can_zero, .can_fua = test_layers_filter_can_fua, .can_multi_conn = test_layers_filter_can_multi_conn, + .can_extents = test_layers_filter_can_extents, .pread = test_layers_filter_pread, .pwrite = test_layers_filter_pwrite, .flush = test_layers_filter_flush, .trim = test_layers_filter_trim, .zero = test_layers_filter_zero, + .extents = test_layers_filter_extents, }; NBDKIT_REGISTER_FILTER(filter) diff --git a/tests/test-layers-plugin.c b/tests/test-layers-plugin.c index 042ecc3..c33d12d 100644 --- a/tests/test-layers-plugin.c +++ b/tests/test-layers-plugin.c @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2018 Red Hat Inc. + * Copyright (C) 2018-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -144,6 +144,13 @@ test_layers_plugin_can_multi_conn (void *handle) return 1; } +static int +test_layers_plugin_can_extents (void *handle) +{ + DEBUG_FUNCTION; + return 1; +} + static int test_layers_plugin_pread (void *handle, void *buf, uint32_t count, uint64_t offset, @@ -186,6 +193,15 @@ test_layers_plugin_zero (void *handle, return 0; } +static int +test_layers_plugin_extents (void *handle, + uint32_t count, uint64_t offset, uint32_t flags, + struct nbdkit_extents *extents) +{ + DEBUG_FUNCTION; + return 0; +} + static struct nbdkit_plugin plugin = { .name = "testlayersplugin", .version = PACKAGE_VERSION, @@ -204,11 +220,13 @@ static struct nbdkit_plugin plugin = { .can_zero = test_layers_plugin_can_zero, .can_fua = test_layers_plugin_can_fua, .can_multi_conn = test_layers_plugin_can_multi_conn, + .can_extents = test_layers_plugin_can_extents, .pread = test_layers_plugin_pread, .pwrite = test_layers_plugin_pwrite, .flush = test_layers_plugin_flush, .trim = test_layers_plugin_trim, .zero = test_layers_plugin_zero, + .extents = test_layers_plugin_extents, /* In this plugin, errno is preserved properly along error return * paths from failed system calls. */ diff --git a/tests/test-layers.c b/tests/test-layers.c index 96df9a6..7757f86 100644 --- a/tests/test-layers.c +++ b/tests/test-layers.c @@ -355,6 +355,12 @@ main (int argc, char *argv[]) "filter1: test_layers_filter_can_multi_conn", "test_layers_plugin_can_multi_conn", NULL); + log_verify_seen_in_order + ("filter3: test_layers_filter_can_extents", + "filter2: test_layers_filter_can_extents", + "filter1: test_layers_filter_can_extents", + "test_layers_plugin_can_extents", + NULL); fprintf (stderr, "%s: protocol connected\n", program_name); @@ -520,6 +526,12 @@ main (int argc, char *argv[]) "test_layers_plugin_zero", NULL); + /* XXX We should test NBD_CMD_BLOCK_STATUS here. However it + * requires that we negotiate structured replies and base:allocation + * in the handshake, and the format of the reply is more complex + * than what we expect in this naive test. + */ + /* Close the connection. */ fprintf (stderr, "%s: closing the connection\n", program_name); request.type = htobe16 (NBD_CMD_DISC); -- 2.20.1